Updates to datetime widget display and function. See #127: https://github.com/southpolesteve/corgi/issues/127

added highlighting for current day when widget is initially displayed

changed display of date format through the widget

style adjustements for today and selected day to avoid potential confusionn

adjusted some behavior and display defaults

removed some commented out code and adjsuted data format tag to correspond with data format from js widget
Merge pull request #140 from southpolesteve/datetime

Datetime picker updates